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  <title>Document</title>
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  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
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    // 
    ul.addEventListener('click', function (e) {
      // 颜色变红色
      // console.log(e.target);
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      // console.log(this);
      e.target.style.color = 'red';
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